(a) Field of the Invention
The field of the invention encompasses tape dispensing and application.
The invention was developed primarily for use in the field of composite technology. In particular, the invention is used in constructing, for example, helicopter rotor blades, rotor blade parts, and other structural and aerodynamic parts of a helicopter. The invention can also be used, however, for the construction of structural and aerodynamic parts of aircraft other than helicopters, for the construction of missiles, satellites, automobile bodies, rail cars, ships and the like.
According to composite technology, a resin pre-impregnated tape having, for example, fiberglass filaments is utilized with or without an additional resin adhesive to construct the particular part desired. The final part is built-up of a successive application of layers of the tape to, for example, a mandrel. The resulting part is light in weight and highly load redundant, so that it is more desirable than a corresponding part made from the traditional materials, such as steel, etc.
(b) Prior Art
In the early days of the development of composite technology the principal means for producing a so-called lay-up, i.e., a shaped but non-structuralized part which has been shaped using a given quantity of tape in one or more layers upon, preferably a mandrel, was by hand. Naturally the procedure was time consuming and consequently expensive.
In the helicopter art, and in particular the rotor blade art, manual procedures are still used to some degree. However, machinery has been developed for replacing to a large extent the known manual procedures. One such machine in the form of a composite tape placement head is disclosed in U.S. Pat. No. 3,775,219. Although it is not evident from the cited patent, the composite tape placement head disclosed is quite large, and consequently represents a significant capital investment. For the purpose of this invention, the portion of the placement head of the cited patent which is of primary interest is the subassembly designated by the letter T. The head T must be rotated at the end of laying each strip of tape on the work piece W. Consequently, the tape must be severed at the end of each tape laying pass. In addition, the tape is drawn from a supply spool by a drive roller, which is situated between the supply spool and a tape placement roller which engages the work piece W. The tape is not drawn by the movement of the applicator head.